Plants convert solar energy into chemical energy through photosynthesis. Eventually they became the fossil fuels that we now use so abundantly. On this page I will focus on human-made solar energy applications in answering part ofyour question: how does solar energy work?

Even then, answering “how does solar energy work?” completely will somewhat depend on the purpose and type of application used to harness solar energy. Some of those aspects are covered more fully elsewhere (diy solar heating). And of course you must have broader solar energy information too.

So, you’re ready to go through this with me now? How does solar energy work?

Let’s go.

Solar energy can be direct or indirect, or active or passive. How does solar energy work" is a question of which the answers can be classified also by focus type.

First, there are two approaches towards solar energy conversion into energy we may use, both involving the use of a solar panel. Let’s start with those shall we? These are

Solar thermal and

Photovoltaic

Solar thermal

The solar thermal method uses energy from the sun directly to generate heat. Solar panels can be used to collect heat from the sun to capture its heat and transfer it for water and space heating in buildings.

Commonly such panels are positioned to maximise absorption of heat from the sun throughout the day and contain tubing through which water circulates. This tubing is known as solar thermal collectors There is also an indirect method where not water but a non-toxic anti-freeze liquid is used. The sun warms this liquid which in turn transfers this heat to water held in a tank. Passive thermal building design is as simple as designing to maximise the sun’s use.

Photovoltaic

This method converts the sun’s power into electricity. This is the photovoltaic process.

Solar cells, or photovoltaic cells are often silicon-based pieces of material that absorb the sun’s light. Not warmth, as in the thermal application

Many of these solar cells are often combined in solar panels

Numbers of solar panels can be combined and interlinked for greater power

Solar energy excites the electrons in the solar cell and electricity is produced

This electricity is in the form of direct current or DC

DC however is not useable for most common purposes

So, next DC power is transformed through an inverter to alternating current, or AC at 120 Volt, a common-use voltage

A small amount of solar energy is lost in this DC to AC conversion but is now ready for distribution to household appliancesnight time use and reduced sunlight

You may be connected to the regular power grid. It may be possible to feed any excess energy that your batteries cannot hold, back to the grid. In this way you may become a green contributor to a public utility.

A further classification that I need to cover in answering your question How does solar energy work? is this one.

Direct and indirect solar energy

Direct solar energy

Using direct solar power involves only one step in transforming it to useable energy, its electromagnetic radiation. Some examples of direct solar energy include

Sunlight striking a solar cell by which electricity is immediately generated

Sunlight that is absorbed by the dark surface warms water in solar thermal collectors

Sunlight absorbed by a fibre optic cable that is fixed on the exterior of a building and lights the inside

Amazingly a solar sail on a spacecraft can move it through the direct force of sunlight. How does solar energy work? Mysteriously it seems sometimes.

Indirect solar energy

You probably guessed it! This process involves more than one step from sunlight to useable energy. Here are some examples

I mentioned photosynthesis already. Plants convert sunlight into chemical energy, including carbon. Biofuel can be made from them as well as methane gas and hydrogen without waiting billions of years for them to turn into fossil fuels, a very indirect method indeed!

Ocean thermal energy is indirect too through its solar-caused differences in temperatures at various depths and wave movement by the wind

After all this, I still have not answered your question: "What is solar energy?" as fully as I might. So, keep moving along with me please…

Active and passive solar energy systems

Passive

A passive system only requires direct sunlight without the aid of any other energy. Sunlight warming an area through a window for example is used in housing and hothouses. Passive solar water heaters for instance use no pump to circulate its water.

Active

And yes, active systems do use the aid of energy besides that of the sun to make them work. Active systems may have electronic tracking devices to maximise sunlight absorption. They may use electric pumps, air blowers, shutters and so on. They can be computer-controlled.

Another way of answering "How does solar energy work?" is by focus type of the solar collector.

Focus types

When very high temperatures are required from solar radiation, its normally diffuse, non-concentrated, light is not enough. Solar energy applications can therefore also be classified as

Point focus

Line focus

Non-focus

Point focus

A saucer-shaped, or parabolic, dish is used to focus diffuse sunlight into a concentrated point of solar radiation. At this point a cluster of solar cells, or a thermal energy receiver convert this radiation into electricity.

Line focus

Same principle as point focus except that here a trough shaped parabolic dish or line of mirrors concentrate the sun’s light which is then converted into electricity.

Non-focus

These systems are those we most commonly think of as solar collectors. Solar thermal panels and solar cell panels are among these. It is an advantage that these systems can use diffuse sun light without further adaptation as above. Concentrating sunlight is of course a more indirect use of solar energy. And greater technological complexity often means higher costs.

Well, that’s it. The basics of how solar energy works. Of course this is only one bit of knowledge that you need if you want to choose the best solar hot water heater, solar energy unit, or even a solar backpack!

You also need to know more if you wish to make your own solar energy system.

Wait, there’s more…

Remember, asking how does solar energy work is not enough. Not if you want a truly sustainable world where all people flourish.

A friend of mine, who is a mother of a son with a disability, visited my web site. Not because she wanted to know theanswers to how does solar energy work? She asked me to expand on "the link between disability and environment" and "how we're all 'cactus' if we don't get our act together and start to take care of one another". My sentiments exactly. I’ll keep reminding you of that.

There’s an art to living with limits, dependency and fragility. Focus on that, take direct action and don’t be passive. It’s called sustainable living.